Missing Person Comparison Request

The FBI administers the National Missing Person DNA Database (NMPDD) as part of the National DNA Index System (NDIS). The NMPDD compares DNA records stored in the Missing Person, Relatives of Missing Person, and Unidentified Human Remains Indexes of NDIS. 

Sufficient DNA data from both the human remains and the relatives of the missing person are needed to produce a statistically significant database association involving DNA profiles in a missing persons case.  In order to maximize the potential for such associations, as much genetic information as possible should be requested and obtained in a missing person investigation. This may be accomplished by:

• Collecting DNA samples from multiple relatives. Any relative of the missing person offering to provide a DNA sample should have a sample collected. The laboratory will assist in determining which samples should be analyzed and databased;
• Requesting mitochondrial DNA (mtDNA) analysis on at least one maternal relative for all missing person cases, regardless of gender;
• Requesting YSTR analysis on at least one paternal relative if the missing person is a male; and
• Requesting mtDNA analysis on all unidentified human remains and YSTR analysis on male remains.

However, despite these efforts, when limited genetic information is available, associations may not be possible through database searches. Circumstances that may prevent a database association from occurring include:

• The DNA data has not been uploaded to NMPDD/NDIS;
• Insufficient STR results were obtained from the human remains;
• The resulting DNA data contains a mtDNA or YSTR haplotype that is relatively common in the relevant population; or
• There is diminished allele sharing between relatives and remains when first-degree relatives (e.g., parents, offspring, or siblings) are not available to provide a sample. 

If a law enforcement agency investigating a case believes that a particular set of remains may be those of a specific missing person, a request for a manual comparison may be warranted. A manual comparison is a direct comparison of the DNA data obtained from specific missing person-related records outside of the routine NMPDD searches.^[1] All requests for manual comparison shall be made by the investigating agency directly to the NDIS participating laboratory responsible for the missing person-related DNA records. Non-law enforcement agencies or organizations seeking manual comparisons should direct their requests to the appropriate investigating agency or medico-legal authority to ensure their involvement in this process. NDIS participating laboratories shall not consider a request for a manual comparison of missing person-related records submitted by a non-law enforcement agency or organization. When a laboratory receives a request for a manual comparison, all available information will be reviewed by the laboratory personnel. This includes not only the DNA data, but other case-specific information (metadata), such as the missing person’s date of disappearance, the date the remains were found, the estimated age of the remains, the age of the missing person, and any other identifying features. 

Using this information, the NDIS participating laboratory will determine whether a routine search of NMPDD would be expected to produce an association. Based upon this review, the laboratory may, in its discretion, deny the request for a manual comparison. If the genetic information from the human remains and/or relatives is limited, the laboratory may perform the comparison in accordance with its policies and protocols. When a manual comparison cannot exclude the possibility of a positive association, the laboratory will provide a report to the investigating agency that includes the appropriate kinship statistics.

If the DNA data for the human remains and reference samples are maintained by multiple NDIS participating laboratories, the laboratories will collaborate to exchange both DNA data and metadata. Once the comparison has been completed, the participating laboratories will ensure that all involved law enforcement agencies, medico-legal authorities, and laboratories are informed of the results.

Note: Please keep in mind that NDIS participating laboratories do not have the legal authority to declare or confirm the identity of human remains. That determination shall be made by the appropriate medico-legal authority (e.g., medical examiner or coroner).

Guidelines for Requesting a Missing Person Manual Comparison

1. All requests for missing person manual comparisons shall be submitted to the NDIS participating laboratory by the law enforcement agency or medico-legal authority responsible for the case.

2. Non-law enforcement agencies or organizations wishing additional information or a manual comparison shall submit the request to the law enforcement agency or medico-legal authority responsible for the case. That agency/authority will forward the request to the appropriate NDIS participating laboratory. NDIS participating laboratories shall not consider requests received directly from non-law enforcement agencies or organizations.

3. If the DNA data related to the case is maintained by multiple NDIS participating laboratories, the requesting agency shall make reasonable efforts to determine the laboratories involved and provide that information with the request for a manual comparison.

4. The NDIS participating laboratory/laboratories maintaining the relevant DNA profiles shall evaluate the data to determine, in its/their discretion, if a manual comparison is warranted. This evaluation shall include:

• A comparison of metadata related to the individual reported missing and the human remains recovered; and

• A review of the available DNA data for completeness, number of available references, and their relationship to the missing person.

5. In the event of a positive association, all law enforcement agencies and medico-legal authorities involved in the case shall be notified by an NDIS participating laboratory. These participating laboratories shall not provide laboratory reports or notifications to non-law enforcement agencies or organizations.

Questions regarding the Missing Persons program within the NDIS should be directed to the FBI Laboratory’s CODIS Unit at 703-632-8315. Questions regarding a specific case or comparison should be directed to the NDIS participating laboratory that maintains the DNA data.

^[1] Known reference DNA records, such as offender and arrestee DNA records, are generally not subject to retrieval from CODIS for manual comparison purposes. Missing person reference DNA records, however, may be retrieved from DNA databases (CODIS) for manual comparison because these reference samples were obtained through a voluntary consent process and were contributed solely for the purpose of identifying a missing or unidentified person.